A method for preparing zinc storage positive electrode material by hydrothermal recovery of waste zinc-manganese dry batteries

Abstract

The invention relates to a method for preparing a positive electrode material for zinc storage by hydrothermal recovery of waste zinc-manganese dry batteries. First, a certain amount of solid alkali is weighed and mixed with a solvent and stirred evenly to obtain a reaction solution. The waste zinc-manganese dry batteries are mechanically disassembled, and the positive and negative electrode wastes are separated and crushed separately for standby use. The crushed positive and negative electrode wastes and the reaction solution are mixed according to a certain solid-liquid ratio, stirred at room temperature for a period of time, and filtered to obtain a filter residue. The filter residue is washed with water several times and then dried to obtain a preliminary recovered raw material. The first step of preliminary recovery of raw materials and additive solution are mixed according to a certain solid-liquid ratio and put into a hydrothermal reactor, a certain proportion of pH regulator is added, and then the hydrothermal reactor is heated at a certain temperature for a period of time. After the reaction is completed, the obtained slurry is filtered to obtain a filter residue, and the filter residue is washed with water and ethanol several times, and then dried to obtain a final recovery product. The present invention reports for the first time a method of obtaining a positive electrode material suitable for aqueous zinc storage by a preliminary room temperature reaction and a final hydrothermal reaction of the positive and negative electrode wastes of waste zinc-manganese dry batteries. This method can avoid the high-temperature calcination operation and the smelting separation using a large amount of acid and alkali in the traditional recycling of waste zinc-manganese dry batteries. It has simple steps and high manganese / carbon recovery efficiency. In addition, the crystal form, size and doping of manganese oxide can be finely controlled by adjusting the recycling steps, and has good practical value.

Description

Technical Field

[0001] The present invention relates to a method for preparing zinc storage positive electrode materials by hydrothermal recovery of waste zinc-manganese dry batteries. The method can avoid the high-temperature calcination operation and the large-scale use of acid and alkali smelting and separation in the traditional waste battery recovery, has simple steps, high manganese / carbon recovery efficiency, and can finely control the crystal form, size, and doping of manganese oxide by adjusting the recovery steps, and has good practical value. Background Art

[0002] Recycling of used alkaline batteries and their electrode materials can avoid environmental pollution and waste of resources caused by landfill or incineration of used batteries. Existing recycling of used alkaline batteries is often accompanied by pyrolysis and hydrolysis. Among them, the pyrolysis step mainly removes organic matter and carbon from the mixed materials by high-temperature calcination to obtain mixed metal oxides. The subsequent hydrolysis step uses acid-base solvents to participate in the dissolution, precipitation and separation and extraction of composite metal oxides.

[0003] Most patents and reports use concentrated acid at normal pressure to recover positive electrode materials. For example, patents (CN 109825708 A, CN106241880B, CN 1120592 A) use high-concentration sulfuric acid or mixed acid to dissolve waste positive electrode materials at normal pressure, and then separate various metal elements in the mixed acid solution by step-by-step precipitation or electrochemical deposition. Another example is patents (CN 112259754 A, CN 112259754 A) use concentrated sulfuric acid or mixed acid and oxidant to dissolve and leach oxides from waste positive electrode materials at normal pressure, and then separate various metal elements by electrochemical deposition, pressurized leaching, etc. Patent CN113299937 A discloses a method of calcining and dissolving a positive and negative electrode mixture with concentrated acid and oxidant, and then adjusting the pH to separate and recover manganese elements. In addition to the concentrated acid treatment method, patents CN115395006 A and CN 1217438 C use solid alkali and ammonia solution to recycle the positive electrode materials of waste dry batteries. Most of the above methods are inseparable from high-temperature calcination and a large amount of high-concentration acid and alkali, the amount of waste liquid is large, and the recovered products are not considered or cannot be directly used as electrode materials for other batteries.

[0004] In view of the above shortcomings, this patent proposes for the first time to hydrothermally treat the mixed positive and negative electrode waste materials of used dry batteries in an acidic buffer solution, and then collect them to obtain aqueous battery positive electrode materials. The present invention avoids high-temperature calcination and concentrated acid treatment, and can realize the recycling of waste battery positive and negative electrode waste materials including manganese oxide, zinc paste, carbon, etc. At the same time, the crystal structure such as the physical phase and size of the recovered manganese oxide can be effectively regulated, and a new method for preparing "manganese oxide / carbon composite positive electrode materials" for aqueous batteries is provided. Summary of the invention

[0005] The technical problem solved by the present invention is to realize the high-efficiency and low-consumption recycling of the recycled materials of the waste dry batteries after the treatment by hydrothermal treatment of the ion acid buffer system composed of ions in the waste dry batteries and the added acidic ion solution, and to prepare the positive electrode material of the aqueous battery with the hydrothermally treated materials.

[0006] The technical solution adopted by the present invention to solve the technical problem is: to treat the materials recovered from the electrode waste of the waste zinc-manganese dry battery by hydrothermal method with an ionic acidic buffer system. The characteristic is that the materials obtained by hydrothermal method can be directly used as the positive electrode material of the aqueous battery.

[0007] The method for preparing a zinc storage positive electrode material by hydrothermal recovery of waste zinc-manganese dry batteries comprises the following steps:

[0008] Step 1: Preparation of battery recycling materials

[0009] 1) Mechanically disassemble the used zinc-manganese dry batteries, and grind and collect the negative zinc metal material and the positive manganese dioxide material.

[0010] 2) Reaction solvent impurity removal

[0011] Weigh a certain amount of one or more of NaOH, KOH and Ca(OH)2 and mix them into a solid base and one or more of water, methanol, ethanol, ethylene glycol, glycerol, N-methylpyrrolidone into a solvent, mix the solid base and the solvent in a certain solid-liquid ratio and stir evenly to obtain a reaction solvent. Mix a certain amount of collected and ground positive and negative electrode materials with the reaction solvent in a certain solid-liquid ratio, and heat and stir the reaction at 0-40°C for 10 minutes to 48 hours to obtain a slurry.

[0012] 3) Powder cleaning

[0013] The above slurry is filtered to obtain gray filter residue and filtrate. The filtrate can be recycled and reused repeatedly. The separated filter residue is washed with water and ethanol several times. The clean filter residue is dried at 60-80°C for 8-15h to obtain preliminary recovered raw materials.

[0014] Step 2: Hydrothermal treatment in acidic buffer system

[0015] 1) Preparation of additives

[0016] Weigh a certain amount of additive and mix it with distilled water to form a solution, stir and dissolve it at room temperature to prepare an additive solution.

[0017] 2) Construction of zinc salt buffer acid system

[0018] Water, the additive solution, the preliminary recovered raw material obtained in step 1 and a pH adjuster are used to form a zinc salt buffer acid system, which is stirred and mixed at a temperature of 20 to 70° C. for 10 to 100 minutes to obtain a recovered raw material ion acid buffer solution.

[0019] 3) Hydrothermal treatment

[0020] The mixed acid solution is transferred to a hydrothermal kettle and hydrothermalized at a certain temperature for a period of time. The hydrothermal solution is filtered, washed with water and ethanol several times, and vacuum dried at 50-100°C for 8-15h to obtain the final recovered product.

[0021] Furthermore, in the step 1.2, the solid base and the dispersant are mixed at a solid-liquid ratio of (0.1-10) g: (10-10000) mL.

[0022] Further: in the step 1.2, the mass ratio of the positive and negative electrode wastes is 0.5 to 1000.0.

[0023] Furthermore: in the step 1.2, the solid-liquid ratio of the positive and negative electrode mixed waste and the composite alkali solution is (0.1-10) g: (10-100) mL.

[0024] Further: In step 2.1, the types of additives are NaCl, KCl, CaSO 4` H2O、MgSO 4` 7H2O、CoSO 4` 7H2O, Fe2(SO4) 3` nH2O、NiSO 4` 6H2O, ZnSO 4` 7H2O、NH4VO 3` One or more 12H2O, the molar concentration of the additive is 0.01~10mol / L

[0025] Furthermore: in the step 2.2, the amounts of water, additive solution, pH adjuster, and preliminary recovered raw material are 1-70 mL, 1-50 mL, 1-70 mL, and 0.1-10 g, respectively.

[0026] Further: In step 2.2, the pH adjuster is one or more of hydrochloric acid, sulfuric acid, phosphoric acid, citric acid, nitric acid, acetic acid and oxalic acid, with a concentration of 0.01 to 10 mol / L.

[0027] Further: in the step 2.3, the temperature of the hydrothermal treatment is 100-160° C., the hydrothermal filling rate is 0.5-0.8, and the duration of the hydrothermal treatment is 4-24 hours.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The invention makes full use of the fact that after the recycled materials are hydrothermally treated in an acidic system, an ion-doped carbon-containing composite material with superior performance can be obtained, which can be directly used as the positive electrode material of aqueous batteries. The invention uses waste dry batteries as raw materials, processes the positive and negative electrode waste materials inside the waste batteries to obtain preliminary recycled raw materials, and hydrothermally treats the obtained preliminary recycled raw materials in an ionic acidic buffer system to obtain an ion-doped carbon-containing composite material, which is expected to provide a new material preparation idea for the positive electrode of manganese-based aqueous batteries while being green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a SEM image of the sample of aqueous battery positive electrode material 1 recovered in Example 1 of the present invention.

[0031] Figure 2 This is the XRD diagram of the aqueous battery positive electrode material 1 sample recovered in Example 1 of the present invention.

[0032] Figure 3 This is a graph of the electrochemical performance of an aqueous zinc ion button battery prepared from the aqueous battery positive electrode material 1 sample recovered in Example 1 of the present invention at different currents.

[0033] Figure 4 The graphs are the cycle performance and coulomb efficiency curves of aqueous zinc ion button batteries prepared from the sample of aqueous battery positive electrode material 1 recovered in Example 1 of the present invention.

[0034] Figure 5 The charge and discharge curve diagram of the aqueous zinc ion button battery prepared from the sample of aqueous battery positive electrode material 1 recovered in Example 1 of the invention.

[0035] Figure 6 This is a CV curve diagram of an aqueous zinc ion button battery prepared from the sample of aqueous battery positive electrode material 1 recovered in Example 1 of the invention.

[0036] Figure 7 This is a SEM image of the aqueous battery positive electrode material sample 2 recovered in Example 1 of the present invention.

[0037] Figure 8 This is a regional enlarged SEM image of the sample of aqueous battery positive electrode material 2 recovered in Example 1 of the present invention.

[0038] Fig. 9 TEM and mapping images of the aqueous battery positive electrode material sample 2 recovered in Example 1 of the present invention.

[0039] Fig.10 This is the HRTEM image of the aqueous battery positive electrode material sample 2 recovered in Example 1 of the present invention.

[0040] Fig.11 This is the XRD diagram of the aqueous battery positive electrode material sample 2 recovered in Example 1 of the present invention.

[0041] Fig.12 This is a graph of the electrochemical performance of aqueous zinc ion button batteries prepared from the aqueous battery positive electrode material 2 sample recovered in Example 2 of the present invention at different currents.

[0042] Fig.13 The graphs are the cycle performance and coulomb efficiency curves of aqueous zinc ion button batteries prepared from the sample of aqueous battery positive electrode material 2 recovered in Example 2 of the present invention.

[0043] Fig.14 This is a charge and discharge curve diagram of an aqueous zinc ion button battery prepared from the aqueous battery positive electrode material 2 sample recovered in Example 2 of the invention.

[0044] Fig.15 This is a CV curve diagram of an aqueous zinc ion button battery prepared from the aqueous battery positive electrode material 2 sample recovered in Example 2 of the invention.

[0045] Fig.16 This is a graph of the electrochemical performance of aqueous zinc ion button batteries prepared from the aqueous battery positive electrode material 3 sample recovered in Example 3 of the present invention at different currents.

[0046] Fig.17 The graphs are the cycle performance and coulomb efficiency curves of aqueous zinc ion button batteries prepared from the sample of aqueous battery positive electrode material 3 recovered in Example 3 of the present invention.

[0047] Fig.18 This is a charge and discharge curve diagram of an aqueous zinc ion button battery prepared from the sample of aqueous battery positive electrode material 3 recovered in Example 3 of the invention.

[0048] Fig.19 This is a graph of the electrochemical performance of aqueous zinc ion button batteries prepared from the sample of aqueous battery positive electrode material 4 recovered in Example 3 of the present invention at different currents.

[0049] Fig. 20 The graphs are the cycle performance and coulomb efficiency curves of aqueous zinc ion button batteries prepared from the sample of aqueous battery positive electrode material 4 recovered in Example 3 of the present invention.

[0050] Fig.21 This is a charge and discharge curve diagram of an aqueous zinc ion button battery prepared from the sample of aqueous battery positive electrode material 4 recovered in Example 3 of the invention.

[0051] Fig. 22 This is a graph of the electrochemical performance of aqueous zinc ion button batteries prepared from the sample of aqueous battery positive electrode material 4 recovered in Example 3 of the present invention at different currents.

[0052] Fig.23 The graphs are the cycle performance and coulomb efficiency curves of aqueous zinc ion button batteries prepared from the sample of aqueous battery positive electrode material 4 recovered in Example 3 of the present invention.

[0053] Fig.24 This is a charge and discharge curve diagram of an aqueous zinc ion button battery prepared from the sample of aqueous battery positive electrode material 4 recovered in Example 3 of the invention. DETAILED DESCRIPTION

[0054] The present invention is further described below in conjunction with the embodiments, and is specifically implemented according to the following implementation method:

[0055] Embodiment 1:

[0056] The invention discloses a method for efficiently recycling waste zinc-manganese dry batteries to prepare positive electrode materials for aqueous batteries. The specific operation scheme is as follows: dismantle the waste zinc-manganese dry batteries, crush the positive and negative electrode materials respectively, and pass through a 150-mesh sieve. Weigh 10g of KOH and dissolve it in 250mL of water to obtain potassium hydroxide lye. Add 4g of the treated positive electrode material and 0.2g of the negative electrode material into 100mL of the lye, and stir for 30min at a temperature of 30°C to obtain a mixed lye. Filter the mixed lye with a sand core funnel to obtain a filtrate and a filter residue, and the filtrate can be recycled and reused. Wash the filter residue with deionized water for 5 times and ethanol for 3 times, collect the filter residue, dry the filter residue in a vacuum drying oven at 60°C for 12h, obtain a recovered material, mix 20mL of H2O, 20mL of 0.01mol / L NaCl solution, 30mL of 3mol / L hydrochloric acid solution and 1g of the recovered material in a beaker, and stir for 30min at a temperature of 35°C to obtain a mixed solution. The mixed solution was added to the inner lining of a 100 mL hydrothermal autoclave, and distilled water was added to make the filling degree 0.7, and the mixture was hydrothermaled at a temperature of 140°C for 12 hours. The mixed solution after hydrothermal treatment was filtered with a sand core funnel to obtain a filter residue, and then the filter residue was dried at a temperature of 60°C for 12 hours, and the aqueous battery positive electrode material 1 was recovered. This material was ground with the conductive agent acetylene black and the binder polyvinylidene fluoride (PVDF) in a mass ratio of 7:2:1 in N-methylpyrrolidone (NMP) solvent until the mixture was uniformly mixed, and then coated on a stainless steel foil, dried at 80°C in a vacuum drying oven for 12 hours, and sliced ​​into 12 mm positive electrode discs; 3 mol / L ZnSO4+0.05 mol / L MnSO4 solution was used as the electrolyte, and a glass fiber separator was used to assemble a 2032 type battery. The constant current charge and discharge test voltage range is 0.8-1.8V, and the current density is 0.1-1.5-0.1A / g; the cyclic charge and discharge test voltage range is 0.8-1.8V, and the current density is 1A / g; the cyclic performance charge and discharge curve of the aqueous zinc ion button battery prepared from the positive electrode material is shown in the figure.

[0057] Embodiment 2:

[0058] The present invention discloses a method for efficiently recycling waste zinc-manganese dry batteries to prepare positive electrode materials for aqueous batteries. The difference from Example 1 is that 30 mL H2O, 20 mL 0.5 mol / L NH4VO3 solution, 20 mL 6 mol / L hydrochloric acid solution, and 1 g of recycled material are mixed in a beaker to recover the positive electrode material 2 for aqueous batteries. The constant current charge and discharge test voltage range is 0.4-1.8 V, and the cyclic charge and discharge test voltage range is 0.4-1.8 V. The remaining steps and parameters are the same.

[0059] Embodiment three:

[0060] The present invention discloses a method for efficiently recycling waste zinc-manganese dry batteries to prepare positive electrode materials for aqueous batteries. The difference from Example 1 is that 40 mL H2O, 20 mL 0.05 mol / L Fe2(SO4)3, 10 mL 6 mol / L hydrochloric acid solution, and 1.0 g of recycled materials are mixed in a beaker to recover the positive electrode material 3 for aqueous batteries. The remaining steps and parameters are the same.

[0061] Embodiment 4:

[0062] The present invention discloses a method for efficiently recycling waste zinc-manganese dry batteries to prepare positive electrode materials for aqueous batteries. The difference from Example 1 is that 40 mL of H2O, 20 mL of 0.01 mol / L KCl solution, 20 mL of 6 mol / L sulfuric acid solution, and 1.0 g of recycled material are mixed in a beaker to recover the positive electrode material 4 for aqueous batteries. The remaining steps and parameters are the same.

[0063] Embodiment five:

[0064] The present invention discloses a method for efficiently recycling waste zinc-manganese dry batteries to prepare positive electrode materials for aqueous batteries. The difference from Example 1 is that 50 mL H2O, 20 ml 0.01 mol / L ZnSO4 solution, 10 mL 2 mol / L acetic acid solution, and 1.0 g of recycled material are mixed in a beaker to recover the positive electrode material 5 for aqueous batteries. The remaining steps and parameters are the same.

[0065] Embodiment six:

[0066] The present invention discloses a method for efficiently recycling waste zinc-manganese dry batteries to prepare positive electrode materials for aqueous batteries. The difference from Example 1 is that 40 mL H2O, 10 mL 1.0 mol / L KCl solution, 20 mL 8 mol / L hydrochloric acid solution, and 1 g of recycled material are mixed in a beaker to recover the positive electrode material 6 for aqueous batteries. The remaining steps and parameters are the same.

[0067] Embodiment seven:

[0068] The present invention discloses a method for efficiently recycling waste zinc-manganese dry batteries to prepare aqueous battery positive electrode materials. The difference from Example 1 is that 40 mL H2O, 10 mL 1.0 mol / L NaCl solution, 20 mL 8 mol / L hydrochloric acid solution, and 1.5 g of recycled material are mixed in a beaker to recover aqueous battery positive electrode material 7. The remaining steps and parameters are the same.

[0069] Table 1 Synthetic materials and electrochemical properties of aqueous cathode materials

[0070]

Claims

1. A method for preparing a zinc storage positive electrode material by hydrothermal recovery of waste zinc-manganese dry batteries, comprising the following steps: Step 1: Preparation of battery recycling materials 1) Mechanically dismantle the waste zinc-manganese dry batteries, and grind and collect the negative electrode zinc metal material and the positive electrode manganese dioxide material; 2) Reaction solvent impurity removal Weigh a certain amount of one or more of NaOH, KOH and Ca(OH)2 and mix them into a solid base and one or more of water, methanol, ethanol, ethylene glycol, glycerol and N-methylpyrrolidone to form a solvent, mix the solid base and the solvent in a certain solid-liquid ratio and stir evenly to obtain a reaction solvent, then mix a certain amount of collected and ground positive and negative electrode materials with the reaction solvent in a certain solid-liquid ratio, and heat and stir the reaction at 0-40°C for 10 minutes to 48 hours to obtain a slurry; 3) Powder cleaning The above slurry is filtered to obtain gray filter residue and filtrate, the filtrate can be recycled and reused, the separated filter residue is washed with water and ethanol several times, and the cleaned filter residue is dried at 60-80°C for 8-15h to obtain the preliminary recovered raw material; Step 2: Hydrothermal treatment in acidic buffer system 1) Preparation of additives Weigh a certain amount of NaCl, KCl, CaSO 4` H2O、MgSO 4` 7H2O、CoSO 4` 7H2O, Fe2(SO4) 3` XH2O、NiSO 4` 6H2O, ZnSO 4` 7H2O、NH4VO 3` One or more additives of 12H2O and distilled water are mixed into a solution and stirred and dissolved at room temperature to prepare an additive solution; 2) Construction of zinc salt buffer acid system Water, the additive solution, the preliminary recovered raw material obtained in step 1 and a pH adjuster are added to form a zinc salt buffer acidic system, and the mixture is stirred and mixed at a temperature of 20 to 70° C. for 10 to 100 minutes to obtain a recovered raw material ion acidic buffer solution; 3) Hydrothermal treatment The acidic buffer solution is transferred to a hydrothermal kettle. The hydrothermal treatment temperature is 100-160°C, the hydrothermal filling rate is 0.5-0.8, and the hydrothermal treatment time is 4-24 hours. The hydrothermal solution is filtered, washed with water and ethanol several times, and vacuum dried at 50-100°C for 8-15 hours to obtain the final recovered product.

2. The method according to claim 1, characterized in that: In the step 1.2, the solid base and the solvent are mixed at a solid-liquid ratio of (0.1-10) g: (10-10000) mL.

3. The method according to claim 1, characterized in that: In the step 1.2, the mass ratio of the positive and negative electrode wastes is 0.5 to 1000.

0.

4. The method according to claim 1, characterized in that: In the step 1.2, the solid-liquid ratio of the positive and negative electrode mixed waste and the mixed solvent is (0.1-10) g: (10-100) mL.

5. The method according to claim 1, characterized in that: In the step 2.1, the molar concentration of the additive solution is 0.01 to 10 mol / L.

6. The method according to claim 1, characterized in that: In the step 2.2, the amounts of water, additive solution, pH adjuster, and primary recovered raw material are 1-70 mL, 1-50 mL, 1-70 mL, and 0.1-10 g, respectively.

7. The method according to claim 1, characterized in that: In the step 2.2, the pH adjuster is one or more of hydrochloric acid, sulfuric acid, phosphoric acid, citric acid, nitric acid, acetic acid and oxalic acid, and the concentration is 0.01 to 10 mol / L.

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